Wireless communication services for mobile vehicles, such as navigation and roadside assistance, have increased rapidly in recent years. Most of the services that have been offered are for a mobile vehicle in operation, but more recently, the demands and potential for services to a turned-off vehicle have grown. Services that may be requested while the vehicle is off or in a quiescent mode may include maintenance and diagnostic functions, system updates, vehicle position determination, unlocking of the doors, or vehicle alarm silencing.
Normally when the mobile vehicle is off, it is placed into a powered-down discontinuous-receive (DRx) cycle. A communication device and a telematics unit on or in communication with each other and with the vehicle may also be placed into a similar DRx cycle to minimize power drain on the battery. To perform a requested function while the ignition is off, the vehicle may be awakened, the desired function performed, and the vehicle subsequently placed back into the DRx cycle.
One method currently in use is to synchronize the wake-up time of the DRx cycle with an incoming call from a telematics or service call center. When the vehicle is awakened, a call may be received and responded to appropriately. The time period between wake-up operations may vary from ten minutes to several days or more if the vehicle has not been moved or driven. To coordinate the wake-up function with the call from the call center, the time at the call center may need to be synchronized with time at the mobile vehicle. A global positioning system (GPS) unit in the mobile vehicle may provide an accurate reading of time. After the call is received and the vehicle responds, the vehicle may be put back into the DRx cycle again after a predetermined duration, minimizing battery drain. The DRx cycle may comprise, for example, awake durations, during which the vehicle may communicate with the call center and sleep durations, during which the vehicle is asleep but capable of being awakened. This DRx cycle may last for a set amount of time.
Unfortunately, a prescribed, coordinated DRx cycle with prescribed sleep interval duration and a prescribed wake-up schedule may not always accommodate the needs of the user or service subscriber. For example, a vehicle in long-term parking at an airport may have been turned off for a period which exceeds the time period allotted for its DRx cycle (e.g., the vehicle has been set to use cycle for three days and the vehicle is left turned off for four days). This becomes a difficulty when the subscriber, upon arriving at his vehicle, requires immediate telematic assistance (e.g., on day four, the subscriber returns to find the keys have been locked in the vehicle and requires telematic assistance to unlock the vehicle.) In another example, a vehicle may enter the DRx cycle too soon (e.g., the vehicle is set to enter cycle as soon as the ignition goes off). This becomes a difficulty when the subscriber, upon turning off the vehicle discovers he needs telematic assistance and must wait until the DRx cycle goes from a sleep interval into a wakeup interval before requesting the assistance.
In addition, when a vehicle awakens, it may be required to register with a local wireless carrier before sending or receiving a call. In certain instances, the time required for responding to a service request or receiving communication, service or software updates for the vehicle and the communication requirements may extend beyond the predetermined awakened duration. In other situations, a call may not be able to be completed during the awakened period due to high call loads on the call center or wireless service provider. Therefore, it may be beneficial to be able to alter wakeup duration and period between wake-ups, accommodating the actual or anticipated requests.
A method is needed to make vehicle services more available even when the vehicle is powered down or turned off. This would result in increased subscriber satisfaction with the services. Increased availability of services is generally compromised by the need to maintain low power consumption.
An improved method may also ease the strain on the call center, for example, by avoiding the need for multiple call attempts to a vehicle during a wake-up period or by allowing the call attempt pattern for contacting numerous vehicles to be staggered or altered. An improved method would further allow an extension of time for the vehicle to complete the requested service during the wake-up period, and an alteration of the predetermined time for initiating the wake-up period. One desirable method improves the availability of a vehicle to receive and perform a service request, while maintaining low power consumption.
Co-pending U.S. patent application Ser. No. 10/011,689 entitled “Method and System for Communication With a Quiescent Mobile Vehicle” by Ronald W. Fraser et al. describes one method of placing the vehicle in a discontinuous receive (DRx) mode, e.g., a mode in which the vehicle can remain in a low-current state for as much time as possible while the vehicle's ignition is off, while occasionally entering an “awake” state for receiving services if necessary. Currently this process of discontinuous receive is accomplished with analog cellular hardware. Analog hardware may limit the amount of time that a vehicle unit can remain awake during an “awake” period.
A method is needed therefore to improve current drain over the analog technology by taking advantage of digital cellular and PCS technology. A method is also needed to enable a vehicle to maintain a DRx cycle in a mixed communication service environment, such as one in which both digital and analog services are available.
It is an object of this invention, therefore, to provide a method for improving the availability of a quiescent vehicle to receive and perform a service request, and to overcome the deficiencies and obstacles described above.